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Semiconductor Physics, Quantum Electronics & Optoelectronics. 2005. V. 8, N 4. P. 014-017.
Some physical properties of Si1-xGex solid solutions
using pseudo-alloy atom model
Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388 120, Gujarat, India
Phone: Head: +91-2692 – 226843; office: +91-2692 - 226844, 226845, 226846 (Ext. 211);
Fax: +91-2692-236475;
E-mail: janiar@rediffmail.com; jivani_a_r @ yahoo.com
Abstract. Some electronic, thermodynamical and mechanical properties of Si1-xGex solid
solution with an arbitrary (atomic) concentration (x) are studied using the pseudo-alloy
atom model. This work is based on the pseudopotential theory of covalent crystals and on
the higher-order perturbation scheme with the application of our proposed model
potential. We have used the latest local field correction function proposed by Sarkar et al.
alongwith other four local-field correction functions of Hartree, Taylor, Utsumi et al. and
Farid et al. to study Si-Ge system. The total energy of the Si1-xGex solid solutions is
investigated and compared with available experimental data. The calculated numerical
values of the heat of solution for Si-Ge system are small and positive. The positive sign
of the heat of solution predicts that, at low temperatures, the phase mixture will be more
stable than the disordered solid solution. Like the case of simple metals, it is seen that a
graph of the ratio of the heat of formations and x(1−x) against x is linear. The bulk
modulus of Si1-xGex is also investigated with different concentrations x of Ge. We have
found in the present study that the bulk modulus decreases linearly with an increase in
the concentration x.
Keywords: pseudopotential method, Si1-xGex solid solutions, the pseudo-alloy atom
model, heat of formation, bulk modulus, elastic constants.
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